The San Francisco 49ers have already been dealt with several injury blows in their preparations for the 2021 season and suffered another setback on Thursday as defensive end Jordan Willis was hit with a six-game suspension.

Willis will miss the opening six games of the campaign for a violation of the NFL Policy on Performance-Enhancing Substances.

While Willis is not a starter on the 49er defense, he figures to serve as a valuable part of their edge rusher rotation following his arrival in a trade from the New York Jets last season.

In seven games with San Francisco in 2020, Willis recorded 2.5 sacks and five quarterback hits, making a strong case to be a key backup for the Niners who can help their pass rush bounce back in 2021 after injuries to Nick Bosa and Dee Ford led to a down year.

But his suspension leaves the 49ers light on reserve options beyond Bosa and Ford for those opening six games. San Francisco brought in Samson Ebukam in free agency as a speed rusher who can fill the void if Ford's troublesome back keeps him off the field while the 49ers are also hoping to harness Arden Key's potential after he posted only three sacks in his first three seasons in the league with the Las Vegas Raiders.

Alex Barrett, who flashed some promise down the stretch last season, rounds out San Francisco's group of edge rushers, which can be considered very shaky even if it does have two elite options in Bosa and Ford.

The Niners are banking on Bosa getting back to his Defensive Rookie of the Year best following the torn ACL he suffered in Week 2 of the 2020 season and that his and Ford's presence allows Arik Armstead to kick inside on passing downs and generate disruption from the interior.

However, with Willis now sidelined, they will be in a precarious position early in the season if Bosa's return does not go as planned and Ford continues to struggle to stay healthy.

San Francisco is a team swimming with elite talent on both sides of the ball, yet there are several areas where depth is clearly an issue. Wide receiver and safety are problem areas in that regard but, following Willis' suspension, edge stands out as the most pressing concern.

Last season, the secondary did much of the heavy lifting in keeping the Niners' defense a top-five unit by Football Outsiders' weighted DVOA. San Francisco will find staying among the elite on that side of the ball significantly easier if they once again have a potent pass rush.

Bosa is the man the 49ers are counting on to provide it, but the depth chart suggests he has little in the way of reliable support. With the likes of Justin Houston and Melvin Ingram still on the market, Willis' suspension may force San Francisco to add a more dependable veteran into the mix.